The idea behind the Green Bay brewery’s Swifts’ Night Ale isn’t just to raise a pint but to also raise awareness of its namesake bird, the chimney swift.

The little birds that fly nonstop during the day and rest in chimneys at night are on the decline, as more chimneys are capped or equipped with smooth liners that prevent the birds from nesting. Sometimes mistaken for bats when in flight near dusk, chimney swifts, often called “flying cigars,” put on acrobatic displays before they drop into tall brick chimneys to roost for the evening.

For the sixth year, volunteers in Green Bay will take part Saturday in a nationwide count of chimney swifts at known roosting spots in and around the city, as the birds rest and gather strength before migrating to South America for the winter. Last year, 15 volunteers counted about 750 swifts, said Nancy Nabak, who co-chairs the local Swift Night Out project with Jim Johnson.

The decline in swifts is worrisome, Nabak said, because they help keep flying insect populations in check in Wisconsin. They eat up to half of their weight in insects, including mosquitoes, every day.

Protected by federal law under the Migratory Bird Treaty Act of 1916, swifts rely almost entirely on man-made structures for nesting and roosting sites. They like chimneys as enclosed overnight roosts, because they offer a rough, vertical surface to cling to that's similar to a hollow tree. The birds, which spend almost their lives in the air, do not perch on branches but use the sharp nails on their feet to cling to the sides of their roost.

A chimney swift roosts in a Green Bay chimney.(Photo: Courtesy of Nancy Nabak)

Titletown brewmaster David Oldenburg researched chimney swifts to come up with a beer that reflects some of their characteristics.

Swifts’ Night Ale is a Kentucky common ale (yes, he checked to make sure there are swifts in Kentucky), a historical style of beer that has been resurrected in recent years. It’s a small-gravity beer, which means less alcohol, and it has a higher level of carbonation than some beers, he said. That lighter, airy quality mimics the light, flighty nature of the bird.

Swifts’ Night Ale will be available until it runs out. Oldenburg expects it to last through September. A portion of proceeds from the beer, as well as special pint glasses and T-shirts available through Nabak, will go to Bird City USA’s local conservation and education efforts.

Swifts’ Night Ale is Titletown's third bird-themed beer. It previously introduced Snowy Owl Session IPA, inspired by a snowy owl that became trapped in the brewery's smokestack and was rescued, rehabbed and eventually released back into the wild. Titletown also created Piping Plover Reserve, a Scottish session ale, in honor of the endangered Great Lakes piping plovers that in 2016 were discovered successfully nesting in Green Bay for the first time in more than 75 years.

“It’s becoming a thing,” Oldenburg said of the bird beers.

Nabak gives credit to Titletown founder and president Brent Weycker for his interest in birds and his support of local bird projects.

“He gets it,” Nabak said. “It really starts with him.”

For bird enthusiasts interested in getting a look at swifts in action as they drop in chimneys at dusk this time of year, Nabak recommends Aldo Leopold Community School, 22 Eliza St., and The Attic, 730 Bodart St.

For information on purchasing Swifts’ Night Ale T-shirts and glasses, email Nabak with “Swifts’ Night Ale” in the subject line at nnabak@sbcglobal.net.